I had them call me today. They were quite polite... When you don't speak English to them. I ALWAYS answer the phone from a number I don't know in Spanish. Hell, my Spanish sucks too, any High School first year Spanish class student is better than me; But that's besides the point here. I always answer the phone with a 'Hola' and say nothing more. Let them do the talking. All you need to know is two more words, 'No' and 'Si'. They figure it out real quick that you don't speak their language(those racist b@stards!) and quickly hang up.
It is still annoying. Research, Marketing all unsolicited and disrupting people's evenings. Should be able to opt out without having to listen to half of the pitch or survey setup. Maybe I should capitalize a few words in my response so you can sense my faux emotion.